docs: def set_label_list(self, label_lists):
          """
          Set the given label-list for this utterance.
          If the label-list-idx is not set, ``default`` is used.
          If there is already a label-list with the given idx,
          it will be overriden.
  
          Args:
              label_list (LabelList, list): A single or multi. label-lists to add.
  
          """
  
          if isinstance(label_lists, annotations.LabelList):
              label_lists = [label_lists]
  
          for label_list in label_lists:
              if label_list.idx is None:
                  label_list.idx = 'default'
  
              label_list.utterance = self
              self.label_lists[label_list.idx] = label_list